The present invention relates to apparatus for accumulating fibrous materials, especially particles of tobacco leaves, into arrays in the form of batches or the like. More particularly, the invention relates to improvements in apparatus for accumulating or forming batches of tobacco shreds or like fibrous materials preparatory to conversion of batches and of additional fibrous material into the filler of a rod of smokable material. Still more particularly, the invention relates to improvements in apparatus of the type wherein batches are formed by admitting fibers into successive pockets which are machined into or are otherwise formed in the peripheral surface of a rotary conveyor.
Commonly owned U.S. Pat. No. 4,009,722 to Wahle et al. discloses an apparatus wherein batches consisting of first fibers are accumulated in the pockets of a rotary conveyor by showering first fibers onto the conveyor and by evacuating air from the pockets during travel below the shower. The batches are transferred onto a second conveyor and the gaps between neighboring batches are filled with second fibers to form a composite stream which is thereupon converted into the filler of a cigarette rod. The second conveyor attracts the batches and the second fibers by suction. It has been found that showering of tobacco particles or like fibrous materials into the orbiting pockets in the periphery of a rotary wheel-shaped conveyor does not invariably ensure the accumulation of batches having a predictable homogeneousness, density and/or other desirable parameters. The situation is aggravated if the rotary conveyor is driven at a high speed as is required in a modern cigarette making plant.
German Offenlegungsschrift No. 34 01 372 discloses means for pneumatically transporting a narrow stream of fibrous material toward the path of orbiting pockets on the rotary wheel-shaped conveyor. The leader of the stream extends radially of the conveyor and its particles are attracted into the oncoming pockets by suction. This proposal renders it possible to enhance the homogeneousness and density of the batches; however, it still fails to provide a solution which ensures the making of satisfactory batches when the wheelshaped conveyor is driven at a high RPM. Therefore, there exists an urgent need to provide an apparatus which can reliably form a succession of batches from fragmentized tobacco leaves or from other fibrous materials of the tobacco processing industry at any desired practical frequency and in such a way that the quality of the batches does not decrease, or does not decrease appreciably, in response to an increase of rotational speed of the conveyor.